type Options struct {
	// Audience is the Secure Token Service (STS) audience which contains the resource name for the workload
	// identity pool or the workforce pool and the provider identifier in that pool.
	Audience string
	// SubjectTokenType is the STS token type based on the Oauth2.0 token exchange spec
	// e.g. `urn:ietf:params:oauth:token-type:jwt`.
	SubjectTokenType string
	// TokenURL is the STS token exchange endpoint.
	TokenURL string
	// TokenInfoURL is the token_info endpoint used to retrieve the account related information (
	// user attributes like account identifier, eg. email, username, uid, etc). This is
	// needed for gCloud session account identification.
	TokenInfoURL string
	// ServiceAccountImpersonationURL is the URL for the service account impersonation request. This is only
	// required for workload identity pools when APIs to be accessed have not integrated with UberMint.
	ServiceAccountImpersonationURL string
	// ServiceAccountImpersonationLifetimeSeconds is the number of seconds the service account impersonation
	// token will be valid for.
	ServiceAccountImpersonationLifetimeSeconds int
	// ClientSecret is currently only required if token_info endpoint also
	// needs to be called with the generated GCP access token. When provided, STS will be
	// called with additional basic authentication using client_id as username and client_secret as password.
	ClientSecret string
	// ClientID is only required in conjunction with ClientSecret, as described above.
	ClientID string
	// CredentialSource contains the necessary information to retrieve the token itself, as well
	// as some environmental information.
	CredentialSource internaldetect.CredentialSource
	// QuotaProjectID is injected by gCloud. If the value is non-empty, the Auth libraries
	// will set the x-goog-user-project which overrides the project associated with the credentials.
	QuotaProjectID string
	// Scopes contains the desired scopes for the returned access token.
	Scopes []string
	// WorkforcePoolUserProject should be set when it is a workforce pool and
	// not a workload identity pool. The underlying principal must still have
	// serviceusage.services.use IAM permission to use the project for
	// billing/quota. Optional.
	WorkforcePoolUserProject string
	// Client for token request.
	Client *http.Client
}